Loading...
The American College of Cardiology/American Heart Association guidelines for heart failure management include a Class I recommendation for exercise training as an adjunctive therapy in patients with symptomatic LV systolic dysfunction (LVSD). The recommendation’s level-of-evidence designation of B reflects the small sample sizes, inconsistent outcomes, and lack of long-term follow-up of existing studies of this intervention. To address these limitations, investigators for the multicenter Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training (HF-ACTION) randomized 2331 adults to receive usual care or exercise training consisting of 36 supervised sessions over 3 months and subsequent home-based exercise, with a target of five 40-minute sessions weekly. All participants (median age, 59) had symptoms of heart failure (NYHA class II in about 63%) and LV ejection fractions ≤35% (median, 25%); a large proportion were receiving evidence-based heart-failure pharmacotherapy.
During a median follow-up of 2.5 years, risk for the primary outcome of death or hospitalization for all causes was lower in the exercise-training group than in the usual-care group (65% vs. 68%; hazard ratio, 0.93), but the difference was not statistically significant. After adjustment for prognostic baseline characteristics, exercise training was associated with significantly lower risks for the primary outcome (HR, 0.89) and the composite of cardiovascular death or hospitalization for heart failure (HR, 0.85). Exercise training was not associated with increased rates of other adverse events. In a separate report of health-status outcomes, the increase in overall Kansas City Cardiomyopathy Questionnaire (KCCQ) score at 3 months was significantly higher in the exercise-training group than in the usual-care group (increases were 5.21 and 3.28 points, respectively). This between-group difference did not increase but remained stable and statistically significant over longer-term follow-up. In a post hoc analysis, 54% of patients in the exercise group had a clinically important increase (5 or more points) on the KCCQ score, compared with 29% in the usual-care group (P<0.01).
O’Connor CM et al. Efficacy and safety of exercise training in patients with chronic heart failure: HF-ACTION randomized controlled trial. JAMA 2009 Apr 8; 301:1439.
Flynn KE et al. Effects of exercise training on health status in patients with chronic heart failure: HF-ACTION randomized controlled trial. JAMA 2009 Apr 8; 301:1451.
Comment
The size, duration, and goals of this study are exemplary. The observed lack of a significant between-group difference in mortality and hospitalization rate precludes definitive conclusions about the beneficial effects of exercise on these outcomes. Although the results of the health status study were statistically significant, the differences were clinically modest. These results support the conclusion that exercise training is safe and confers modest benefits to patients with symptomatic LVSD; whether the cost of such an intensive intervention is worth the benefits remains to be seen.